Add "View Samples" Action from Schema Explorer to Graph View

## Problem

When exploring the schema, users may want to quickly see real data for a given node or edge type. Currently, there is no direct way to navigate from the Schema Explorer to the Graph View with sample instances of a selected type loaded.

## Proposed Solution

Add a button or link on node/edge types in the Schema Explorer that navigates the user to the Graph View with sample instances of that type loaded. This could work by:

- Navigating to the Graph View and executing a search filtered to the selected type, or
- Navigating to the Graph View and directly adding a small set of sample nodes/edges of that type to the canvas.

## Acceptance Criteria

- [ ] Each node/edge type in the Schema Explorer has an action to view samples.
- [ ] Clicking the action navigates to the Graph View with sample data for that type visible.
- [ ] The transition is seamless — the user does not need to manually re-enter the type or configure a search.

Start at the Schema Explorer and Graph View entry points to trace how a selected node or edge type is represented and how navigation or searches are initiated. Compare the proposed filtered search and direct sample-loading approaches, then verify that every type exposes an action and that the Graph View displays the selected type's samples without manual configuration.

Written by the indexing model from the issue text.